If Bret “Biku” Shimabuku is playing music, teaching music, thinking about music or present in a room where music will be played, he’s right where he wants to be.

“I just like being around music,” he says.

He’s got the poise and positivity of an athlete and a mentor — as a former world-class paddler and longtime teacher, he has the ability to stay chill while challenges and chaotic events unfold around him. And he has the determination of a survivor — having bounced back from a near-fatal heart attack.

You see it all on display as Shimabuku rides herd on an ever-rotating lineup of unruly musicians, as maestro of Rising Melody. The weekly showcase for original music takes place each Tuesday at the Downbeat Lounge in Chinatown.

Shimabuku projects an aura of calm. He’s congenitally upbeat and encouraging, with a smile typically playing across his face. Present him with a problem and he’ll reach for a solution, and look for the silver lining.

The habits are valuable for a music teacher, who must encourage his students to believe in themselves and to reach inside for creative interpretations. They’re also a reflection of Shimabuku’s inner strength.

It’s no easy task to wrangle the dozens of teenage and adolescent boys that he mentors as band director of the Saint Louis School music program. And it’s no easier to helm Rising Melody.

Week by week, song by song and session by session, Shimabuku works to build up a community of musicians at the showcase event.

“I’m trying to build momentum and trying to get people aware of it,” he said. “I want to build a scene — something in the community that’s well-known and established.”

He began teaching at Saint Louis seven years ago, wading into the maelstrom of education for teenage boys of varying levels of self-control and musical ability. His roles include guiding students in the classroom and leading the band at public and campus-related events.

Enthusiasm for music class and band has grown on campus since Shimabuku came on, with 90 middle school and high school students taking classes this year.

“When I started working at Saint Louis, I kind of had to put my head down and build the band program,” he said. “I think I’ve done that.”

In the classroom, where he’s called “Mr. S,” some boys pay rapt attention; others can hardly remain seated.

Shimabuku’s technique is to stay positive and focused on the music.

“Even if they go back and remember, ‘Oh, I was such a troublemaker,’ they will remember the music, too,” he said, after one spring class.

“It’s definitely like performing. I have to command the audience’s attention,” he noted. “I’m constantly performing and trying to entertain.

“I’m trying to keep everyone motivated, to know that they’re a team, that they can play it together,” he said. “Even for me, it’s motivating. I know it can happen, but when it does, it’s a good feeling!”

Born in 1979, Shimabuku knows about teamwork. As a high school student at the University Laboratory School, he was a two-year champion ILH paddler. He went on to be accepted to the U.S. Junior World Team as a flat-water sprinter, training with Olympic-level paddlers and competing in Finland and Poland.

It was an “all-encompassing” time of his life, Shimabuku recalls, but ultimately, he decided to move on from athletic competition. He attended college at Colorado State where, career-conscious and planning for a life in the islands, he studied the business of tourism and outdoor recreation — and paid his way through school as a guitar instructor.

In 2014, a sudden heart attack felled Shimabuku on a Pahoa street during an evening run.

The heart attack might have been deadly, had a father and son driving by not seen Shimabuku fall. The pair administered CPR, called 911 and saved his life. The twist: The young man in the car, Matthew Ornelles, was a senior at Saint Louis.

Shimabuku doesn’t remember that day, but the experience of surviving it has changed him, he says: He’s more focused on meeting his goals, more conscious of how important music is in his life, more aware of the value of time.

“I’m not really religious, but for me, music is like that,” he said, earnestly, comparing his devotion to music to a higher calling.

He’s studied guitar, bass and piano, and has recently been writing new songs.

“I’m alive right now, and music is my favorite thing. I just want to experience that before, I guess, I die,” he said.

His work with Rising Melody artists gives him inspiration, as well. He has thoughts of setting up a traveling showcase of some of the islands’ best, “somewhere down the road.”

“I’m just ready for anything. Whatever grand adventure comes my way, whether taking Rising Melody on the road or putting together a performance for schools — I take everything day to day,” he said. “But I do feel an urgency to share my art.”

Rising Melody was conceived as a showcase for original music by local musicians. Between 2006 and 2009, it had a home in Chinatown at the now-defunct thirtyninehotel. Shimabuku would often be heard playing melodic guitar tunes and singing at the original site, alongside a rotating cast of music makers.

He built up a following, and a roster of players who were eager to be heard.

After leaving thirtyninehotel, Rising Melody went to other locations in Honolulu. Shimabuku’s showcase found another long-standing home at Coffee Talk, a Kaimuki gathering place that was open to all ages. “That open mic was real successful,” Shimabuku said. “We had a lot of kids coming in.”

Musicians come in for different reasons. Some have a passion for it; others do it for fun. He feels a common bond with those who “want it so bad” that they have to show up and play, but respects each player’s motivations.

The common thread in all locations has been Shimabuku’s enthusiasm, and the camaraderie between musicians.

“Anything I can do feels like part of my mission,” he said.

At Rising Melody’s current location, Downbeat, where Honolulu musician James McCarthy first launched a Tuesday showcase a few years back, musicians get paid for their performances. Shimabuku is enthusiastic about that aspect of the series.

“I love it,” he said. “I get to hire musicians who really love it. They write their music. It’s important to them.

“People know now,” he said. “It’s catching on.”

As a singer, guitarist and songwriter, Shimabuku’s current, urgent goal is to record his own music. “That’s something I have to bring out right now,” he said. “I would like to shift toward performing more, and that’s why I shifted toward Rising Melody at Downbeat. It’s a platform.”

He often performs with his sister Jaena, appearing as the Shimabukus. Jaena Shimabuku is present at nearly every showcase; like her brother, she’s an exceptionally supportive, positive presence.

“He’s on point every time,” she says of her brother. “He has precision, with soul.”

Two years younger, Jaena Shimabuku was the first to immerse herself in music; she started asking for ukulele lessons as soon as she could recite the alphabet, and studied voice with Melveen Leed.

“We inspired each other,” she said. “I was a little more folky, I guess. He was a little more punk rock.”

Both are working on their own recording projects, though they’ll also work together. “We’re like a team,” she said, smiling. “Rising Melody keeps us closer.”

Rising Melody balances out his life, Bret Shimabuku said. “It’s a labor of love.”

With music, Shimabuku has found a means of making a living and making a life. Performing, producing, teaching, surviving as a musician and a human being all take courage, he observed. He hopes to reflect that in his work.

“The more aware and grateful you are in life, the more you can do with it,” he said. “It’s like a story. I just want to live the best story.”